Process of manufacturing nitric acid.



F. S. VALENTINER.

PROCESS OF MANUFACTURING NITRIC ACID.

APPLICATION FILED MAR. 30. 1907.

7 20 224 Patented May 4, 1909.

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RlEnRmH mum. ALENTINER, i B1 WSWMW FRIEDRICH SAMUEL VALENTINER, OF LEIPZIG-PLAGWITZ, GERMANY, ASSIGNOR TO THE FIRM OF VALENTINER'AND SGHWARZ, OF LEIPZ'IG-PLAGWITZ,GERMANY.

.PROQESS F MANUFACTURING NITRIC ACID.

No.'92o,224.

Specification of Letters Patent.

- Patented May 4., 1959.

Application filed March so, 1907. Serial No. 365,486.

Germany, and resident of Leipzig- Plagwitz,

Germany, have invented a certain new and a useful Im 'rovement in Processes of Manufectlypure nitric acid in a shorttime.

. place.

facturing itric -Acid, of which the following is a-speeification.

This invention relates to a process'of obtaining very highly concentrated and per- It has been shown that the decomposition of nitrate of sodium or other nitrates in a vacuum or in rarefied air takes place much more re. idly when provision is made for surrounc ing the nitrate of sodium on all sides during ,the entire operation with the uantity of sulfuric acid necessary for the recom osition. r

In t 1e production of nitric acid according to vacuum processes heretofore in use there was a certain vacuum throughout the entire apparatus. vantage was experienced that the nitrate of sodium remained floating on the sulfuric acid, and therefore a slower distillation took Experiments have shown that the distillation can be effected more rapidly by working with increased pressure in the retort.- say with a pressure exceeding that of the atmosphere y an amount equivalent to a column of mercury of 150 mm. or less, but with rarefied air in the condenser at about 610 'mm. vacuum. For this urpose the nitric acid gases evolved are t rottled at the point where they leave the retort on their way to the condenser, the passage being I at-this point half the diameter of the condensation coil. The gases, evolved during the distillation do not pass freely through the constriction and therefore cause the ni-- trate of sodiumto remain immersed in the sulfuric acid, while there is a vacuum in the condenser. The action of the sulfuric acid -is considera ly reduced. The throttled gases pass into a cooling coil in which they are artly condensed, the outflow pipe leading 3 rom which is made long enough to extend to the base of the first receiving vessel. The condensed nitric acid collects here and forms On this i account the disad.

a liquidseal. The uncondensed gases following are forced to pass through the nitric acid and escape .With the gaseous im urities N0 HCl, etc. and pass into a secon and a third receptacle in order to be treated there in the same manner. The nitric acid 30 obtained is free from lower oxide of. nitrogen and chlorin compounds. The latter are caught by suitable receiverspand rendered innocuous to the air pump.

In the drawing is shown'by way of example one suitable construction of apparatus for carrying the process into effect.

Asshown, 1 is the retort: 2 is a plate with a small opening for producing the difference of pressure between the retort and the receiverr3 is the connection to the cooling coil 4 contained in a suitable cooling vessel. the end of the cooling coil issuing from the cooling vessel is connected a glass tube 5 connected to a delivery tube which extends almost to the bottom of the first receiving vessel 6 whereby the distilled nitric acid forms a liquid seal 8. 9 is connecting pipe to the next receiving vessel.

10 is a three-way cock which provides a I connection of'the cooling coil 4 either with the first receiving vessel 6 or with a tube 11 leading to the next receiving vessel.

12 a suction pipe by means of which the air is withdrawn from the receiving vessel 6 to maintain the re uired vacuum.

It will be seen t at the action of the hot gases flowing into the vessel 6 and issuing through the i e 9 willitself produce the purification o t e condensed acid in the vessel 6, and the condensed acid remains pure since the impurities do not return to the rev nitrate and sulfuric acid by thrott ing the nitric acid gases passing 'from'the retort, maintaininga artial vacuum in the condenser, and purifying the collecting condensate by forcing therethrough the following uncondensed nitric acid ases. I

'52. The process of rapidly obtaining highly concentrated nitric acid, which consists'in In testimony whereof I have. signed my subjecting-in a retort sodium nitrate to the name to this specification in the presence of action of sulfuric acid, throttling the escape two Subscribing Witnesses. of the evolved gases to the condenser, con- FRIEDRICH SAMUEL VALENTINER. 5 densing.the nitric acid gases, and purifying Witnesses: the condensate by passing therethrough the RUDOLPH FRIOKE,

uncondensed gases issuing from the retort. SOUTHARD P. WARNER. 

